How to fill the array if there are not enough array elements in php

Two methods for PHP to fill an array: 1. Fill the array to the specified length with the specified value through array_pad(), the syntax is "array_pad(original array, length, specified value)". 2. Fill the array to the specified length with the specified value through array_fill(), the syntax is "array_fill (start filling position, filling length, specified value)".

The operating environment of this tutorial: windows7 system, PHP version 8.1, DELL G3 computer

PHP provides 2 types of fill arrays Function to a specified length:

• array_pad(): Fills an array with a given value

• array_fill(): To fill Create a new array using the data method

1. Use array_pad() to fill the array

array_pad() function can fill the array with a certain value to the specified length, the syntax is as follows:

array array_pad ( array $arr, int $size , mixed $value )

Parameter description:

• arr represents the array to be filled.
• size represents the length to be filled:
  • If size is a positive number, fill to the right side of the array;
  • If size is a negative number, start from the left Filling;
  • If the absolute value of size is less than or equal to the length of the arr array, there will be no filling.
• value represents the value to be filled.

array_pad() function will fill the array arr to the length size with the value value.

Return value: Return the filled array. The returned array is just a copy, the original array will not be changed.

Usage examples are as follows:

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);
$arr = array(12, 10, 9);
$result = array_pad($arr, 5, 0);  //从数组右侧开始, 用0填补数组到含有5个元素
var_dump($result);
$result = array_pad($arr, -7, -1);  //从数组左侧开始, 用-1填补数组到含有7个元素
var_dump($result);
$result = array_pad($arr, 2, "noop");  // 第二个参数小于数组长度, 不填补
var_dump($result);
?>

2. Use array_fill() to fill the array

array_fill() function A new array will be created by filling data, or a certain value will be used to fill the array to the specified length. The syntax is as follows:

array array_fill ( int $start_index , int $num , mixed $value )

Parameter description:

• start_index means Array index, that is, where to start filling the array:
  • If start_index is a non-negative number, the index of the array will start from start_index and end with start_index num - 1;
  • If start_index is a negative number, the array The index of will consist of start_index, 0, 1, 2, ..., num-1.
• num represents the length to be filled.
• value represents the value to be filled.

array_fill() will create a new array containing num elements, where the value of each element is value. Unlike array_pad(), array_fill() creates a new array by filling it, rather than based on the original array.

Return value: Return the new array after filling.

Usage examples are as follows:

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);
$a = array_fill(5, 6, &#39;banana&#39;);  //使用banana填充数组到6个元素, 索引键由数字5开始
$b = array_fill(-2, 4, &#39;pear&#39;);  //使用pear填充数组到4个元素, 索引键由-2开始
$c = array_fill(3, 2, array(1,2,3));  // 用一个数组填充成一个二维数组
var_dump($a);
var_dump($b);
var_dump($c);
?>

Recommended learning: "PHP Video Tutorial"

The above is the detailed content of How to fill the array if there are not enough array elements in php. For more information, please follow other related articles on the PHP Chinese website!